Fluid-pressure brake.



2 SHEETS-SHEET 1.

PATENTED JAN. 1, 1907.

A. PARKER-SMITH. FLUID PRESSURE BRAKE. APPLICATION rmui JULY 16 lvi/tmcmea THE Nam-us PE No. 839,882 PATENTED JAN. 1, 1907. A. PARKER-SMITH.

FLUID PRESSURE BRAKE.

APPLIOATION FILED JULYIB, 1906.

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, lVif-rwmeo UNITED STATES PATENT OFFICE.

AUGUSTUS PARKER-SMITH, OF NEW YORK, N. Y., ASSIGNOR, BY MESNE ASSIGNMENTS, TO SAUVAGE SAFETY BRAKE COMPANY, A CORPORA- TION or NEW JERSEY.

FLUID-PRESSURE BRAKE.

Specification of Letters Patent.

Patented Jan. 1, 1907.

Application filed July 16, 1906. Serial No. 326.383.

To all whom it may concern:

Be it known that I, AUGUSTUS PARKER SMITH, a citizen of the United States of America, and a resident of the borough of Manhattan, city, county, and State of New York, have invented certain new and useful Improvements in Fluid-Pressure Brakes, of which the following is a specification.

My invention relates to fluid-pressure brake systems in general, and more specifically consists of an improvement on the apparatus disclosed in patent to William H. Sauvage, No. 825,077, dated July 3, 1906. In said patent mechanism is shown in which two cylinders arranged to force out their pistons in opposite directions exert different amounts of pressure upon the brake-shoes through the intervention of different lever. systems.

My invention is designed to simplify said leverage systems and other details of the apparatus disclosed in the Sauvage patent.

The best form of apparatus embodying my invention at present known to me is illustrated in the accompanying two sheets of drawings, in which- Figure 1 is a planview, inpartial section, of apparatus embodying my invention, parts being shown in diagram Fig. 2 is a detail diagrammatic view of one modification. Fig. 3 shows a second modification, and Fig. 4 is a detail diagrammatic view of a third modification.

Throughout the drawings like referencefigures indicate like parts.

The right-hand cylinder 1 is called the first or main cylinder. It contains the usual piston 2 and piston-rod 3. The left-hand cylinder 4 is called the second or auxiliary cylinder and has piston 5 and pistonrod 6.

7 is the inletpipe, through which the air or other fluid under pressure is admitted to the first cylinder.

8 is the crossover-pipe, having port 9 arranged five or six inches from the cylinder head of the main cylinder and extending to the auxiliary cylinder.

13 is a brake-lever pivoted to piston-rod 3 at 17.

16 is a second brake-lever pivoted to the piston-rod 6 at 20.

10 is a clutch-clog pivoted to the head of drawings.

the first cylinder in any convenient manner, as by means of the hook and beveled portion 10*, and 11 is a spring normally pulling said dog to the left, so as to prevent movement of the piston-rod 3 toward the left.

12 is a tappet-rod pivoted to the free end of the dog 10 at 15 and having its other end 12 yoked over the piston-rod 6 and adapted to be struck by the piston-rod head 6 when the piston 5 is in its inmost position.

14 is a tie-rod pivoted to the brake-lever 13 at 18 and to the brake-lever 16 at 21.

23 is a top rod connected to the brakelever 13 by the pivot 19.

24. is a top rod connected to the brakelever 16 by pivot 22,

25 represents the live lever; 26, the dead lever 27, .the bottom rod, and 28 28 the brake-shoes on the right-hand truck.

29 represents the live lever; 30, the dead a lever; 31, the bottom rod, and 32 '32 the brake-shoes on the left-hand truck.

It will be noted that the distance from the pivot 17 to pivot 18 is less than from the pivot 20 to pivot 21 and, conversely, that the distance from the pivot 18 to the pivot 19 is more than from the pivot 21 to the pivot 22. As shown in the drawings, the distance from 17 to 18 is one-half of that from 20 to 21 and the distance from 18 to 19 twice the distance from 21 to 22, the brake-levers being the same length. .In the same way the distance from the centers of the brake-shoes 28 28 to the point of pivotal connection of the live and dead levers with the bottom rod 27 is less than the distance from the centers of the brake-shoes 32 32 to the pivotal connections with the bottom rod 31, the live and dead levers being shown the same length in the As shown, the distance from the bottom rod to the center of the brake-shoes 28 28 is onehalf of the distance from the other bottom rod to the centers of the brakeshoes 32 32. Such being the proportion of the parts, it is evident that if the piston-rod 3 is driven out with a force of ten pounds it will produce a rapid movement of the wholelever system, quickly taking up the brakeshoe clearance and slack and setting the brakeshoes with a moderate pressure. The force transmitted to the top rod 23 would be five units and that transmitted to the top rod 24 ten units, with the proportions shown in Fig.

1, where the length of the live lever 25 is eight times the distance from the bottom rod 27 to the center of the brake-shoe 28, and the length of the live lever 29 is four times the distance from the bottom rod 31 to the center of the brake-shoe 32. This would cause a brake-shoe pressure of forty units in each case and produce a theoretically correct brake-lever system. When the piston 2 has passed the port 9, of course air will cross over through the pipe 8 to cylinder 4 in the wellknown way, and the second piston 5 will begin to move toward the left. lease the yoked end of the tappet-rod 12 and permit the spring 11 to vibrate the clutchdog 10 slightly toward the left, immediately grasping the piston-rod 3 and preventing any backward motion of the first piston 2 which would tend to occur, as the force of this piston would be overpowered by the force of the second piston 5 transmitted through the multiplying-lever system shown. If the second piston 5 be forced out with a force of ten units, it would evidently produce on the top rod 24 a pull of twenty units and on the top rod 23 a pull of ten units. These unequal pressures would again be equalized by the unequal leverage of the live levers and produce a uniform brake-pressure of eighty units on all the brake-shoes-that is to say, the second cylinder would exert double the braking force of the first cylinder. When the air is released and the second piston reaches its inmost position, the piston-rod head 6 would strike the yoked end of the tappet-rod 1.2, force the dog 10 back into its original position, release the piston-rod 3, and permit the first piston also to come home.

In the modification shown in Fig. 2 in diagram the lever-arms of all the live and dead levers are shown of the same proportion, the distance from the bottom rod to the center of the brake-shoes 32 being one-eighth of the length of the live and dead levers 29 and 30, the same as with the live and dead levers 25 and 26 on the other truck. In this case the equalization of brake-shoe pressure is produced by the introduction of a subsidiary lever 33, having one end fulcrumed on the carbody, while its other end is connected by the subsidiary top rod 24 with the live lever 29, and the top rod 24: is connected to the middle portion of the lever 33. An adjustable nut cooperating with dog 10 is substituted for hinge 15.

In the modification shown in Fig. 3 all the live and dead levers are given'the proportions of four to onethat is to say, the distance from the bottom rod to the center of the brake-shoes is one-quarter of the length of each lever. Here the equalization of brakeshoe pressures is produced by doubling the pull of the top rod 23 through the interven tion of the chain 34, one end of which is made fast to the car-body at 35 and the other end This will reto the top of the brake-lever 13, while the pulley 36, placed in the bight of the chain, has its journals mounted on or connected to the live lever 25.

In the modification shown in Fig. 4 the same effect is produced by substituting for the chain and pulley its mechanical equivalent-the subsidiary lever 37, having one end pivoted to the car-body, while the other end is pivoted to the top rod 23, and the subsidiary top rod 23 connects the middle portion of lever 37 with the live lever 25.

The advantages of my invention comprise the simplification of the compound-lever system necessary to produce different brakeshoe pressures from cylinders of the same or approximately the same crosssection and the reduced cost and greater simplicity of the clutch-dog construction.

It is evident, of course, that various changes could be made in the details of construction illustrated and described without departing from the spirit and scope of my invention. Other means for producing the successive action of the two cylinders might be used, the two cylinders need not necessarily be placed in line one with another, the proportions of lever-arms shown may be widely varied, the brake-levers 13 and 16 need not be of the same length, &c., but

these and other features would simply produce changes in form, but not in principle.

Having,. therefore, described my invention, I claim- 1. In a fluid-pressure brake apparatus, the combination of two cylinders, pistons and piston-rods, means for causing said pistons to move successively in opposite directions, two brake-levers of equal length having their inner ends pivoted to the respective piston-rods, a tie-rod pivoted to the brakelevers, the connection to the brake-lever pivoted to the piston-rod first given motion being nearer to the piston-rod pivot than the connection to the other brake-lever is to its piston-rod pivot, and a system of levers and rods extending from the outer ends of the brake-levers to the brake-shoes.

2. In a fluid-pressure brake apparatus, the combination with a connected system of levers and rods, of two cylinders, pistons and piston-rods, means for causing said pistons to move successively in opposite directions, two brake-levers having their inner ends pivoted to the respective piston-rods, and a tierod connecting said brake-levers at points dividing them into oppositely-disposed unequal leverar1ns.

3. In a fluid-pressure brake apparatus, the combination with a system of connected levers and rods, of two cylinders, pistons and piston-rods, means for causing said pistonrods to move successively in opposite directions, two brake-levers connecting said piston-rods with the other portions of the brake system and a tie-rod connecting the brakelevers at points which form two unequal leverage systems, the lever producing the greater multiplication of piston thrust being connected to the piston-rod which last begins to move.

4. In a fluid-pressure brake apparatus, the combination with a system of connected levers and rods, of two cylinders, pistons and piston-rods, means for causing said pistonrods to move successively in opposite directions, two brake-levers connecting said piston-rods with the otherportions of the brake system and a tie-rod connecting the brakelevers at points which form ,two unequal leverage systems, the lever producing the greater multiplication of piston thrust being connected to the piston-rod which last begins to move, together with means for equalizing the brake-shoe pressures.

5. In a fluid-pressure brake apparatus, the combination with a system of connected levers and rods, of two cylinders, pistons and piston-rods, means for causing said pistonrods to move successively in opposite directions, two brake-levers connecting said piston-rods with the other portions of the brake system and a tie-rod connecting the brake-levers at points which form two unequal leverage systems, the lever producing the greater multiplication of piston thrust being connected to the piston-rod which last begins to move, together with means for equalizing the brake-shoe pressures, said last-mentioned means comprising a subsidiary lever inserted in the top rod on the side producing the lessermultiplication of piston thrust.

6. In a fiuid-pressure brake apparatus, the combination of two cylinders of the same diameter placed back to back and provided with pistons and piston-rods, means for causing movement of the second piston only after movement of the first piston has begun, two brake-levers of equal length having their inner ends pivoted respectively to the two piston-rods, and a tie-rod pivoted to the brake-lever connected to the first piston at a point near the inner end, and pivoted to the other brake-lever at a point nearer its outer end.

7. In a fluid-pressure brake apparatus, the combination of two cylinders of the same di ameter placed back to back and provided with pistons and piston-rods, means for causing movement of the second piston only after movement of the first piston has begun,

two brake-levers of equal length having;

their inner ends pivoted respectively to the two piston-rods, and a tie-rod pivoted to the brake-lever connected to the first piston at a point near the inner end, and pivoted to the other brake-lever at a point nearer its outer end, together with a system of connected levers and rods extending from the outer ends of the brake-levers to the brake-shoes, and means for equalizing the brake-shoe pressures.

8. In a fluid-pressure brake apparatus, the combination of two cylinders of the same diameter placed back to back and provided with pistons and piston-rods, means for causing movement of the second piston only after movement of the first iston has begun, two brake-levers of equal length having their inner ends pivoted respectively to the two piston-rods, and a tie-rod pivoted to the brake-lever connected to the first piston at a point near the inner end, and pivoted to the other brake-lever at a point near its outer end, together with a system of connected levers and rods extending from the outer ends of the brake-levers to the brake-shoes, andv means for equalizing the brake-shoe pressures, said, means comprising a multiplyinglever system inserted in the top rod on the side of the first cylinder.

9. In a fluid-pressure brake apparatus, the combination of two cylinders of the same diameter placed back to back and provided with pistons and piston-rods, means for causing movement of the second piston only after movement of the first piston has begun, two brake-levers having their inner ends pivoted respectively to the two piston-rods, a tie-rod connected to the lever on the side of the first cylinder at a point one-third of the distance from the inner to the outer end of that lever, and to the other lever at a point two-thirds of the distance from its inner to its outer end, a system of connected levers and rods extending from the outer ends of the brake-levers to the brake-shoes, a chain connected at one end to the outer end of the brake-lever on the side of the first cylinder and at the other end to the car-body, and a pulley inserted in the bight of said chain and having its journals connected to the live lever on the truck at that end of the car.

Signed at New York, N. Y., this 13th day of July, 1906.

AUGUSTUS PARKER-SMITH.

Witnesses WILLIAM ENNIS, M. G. CRAWFORD. 

